The present invention relates to bakeware such as cookie sheets, cake pans, pizza pans, jelly roll pans, and the like. Over the years, such bakeware items have been made of various materials, including, for example, steel, tin, and aluminum.
In some cases, the structural material which comprises the cookie sheet is coated with a non-stick material, such as a polymer. However, such polymers have difficulty withstanding the heat to which bakeware is exposed. In particular, many non-stick surface treatments cannot withstand direct heat such as that which occurs in a broiler. In addition, non-stick surface treatments which are polymeric in nature have very low scratch resistance. As a result, the user is often required to use special plastic spatulas and must handle the bakeware carefully. Even when special hand implements are used with such non-stick polymeric coatings, the coating tends to deteriorate through normal wear and tear such as that which results from washing and stacking of the bakeware.
Polymeric non-stick coatings can significantly affect the cost of producing bakeware. Depending upon the coating applied, special processes may be required to ensure that the coating adheres to the metal comprising the bakeware.
Another disadvantage of some bakeware items is the tendency for the bakeware to become stained. In particular, smooth surfaces on bakeware tend to make stains readily visible. Such stains can be the result of corrosion, or dyes which are present in food which has been cooked on the bakeware, or from burnt food.
It is, therefore, an object of the present invention to provide bakeware which is both scratch and stain resistant.
It is another object of the present invention to provide bakeware which is both economical and attractive.
Another object of the present invention is to provide bakeware which retains its attractiveness over a long period of time, despite repeated rough usage.
A further object of the present invention is to provide bakeware which has a non-stick surface without the use of a polymeric coating.
Still another object of the present invention is to provide low cost bakeware which has a high degree of releasability.
Yet another object of the present invention is to provide bakeware which retains its releasability despite repeated rough usage.
These and other objects of the present invention are achieved with bakeware which includes an aluminum sheet having a texturized upper surface. The texturing is comprised of a plurality of protrusions of various sizes. The protrusions are generally rounded, so as to create a generally undulating surface. The difference between the highest point and the lowest point of the undulating surface (the "textural differential") is preferably about 0.007 inch, and the frequency of the protrusions is preferably about 27 protrusions per square inch.
In one embodiment of the invention, the aluminum sheet having the undulating upper baking surface is attached to a second lower sheet to form an insulated baking device. In a second embodiment of the invention, a single aluminum sheet having an undulating upper baking surface has a series of holes which allow additional heat to flow to the underside of food which is baked on the upper undulating surface. Further texturing may be employed by superimposing a second surface feature on the upper undulating surface of the bakeware. The second feature includes a relatively large number, preferably about 175 per square inch, of smaller crater-like depressions which are present both on and between the undulating protrusions.